Carburetor



Patented Apr.. 7, i925.

narran stars naar ff CHARLES E. WILLIAMS, OF DETROIT, MICHIGAN, ASSIGNOR T0 GENERAL MOTORS CR- PORATIO'N, 0F DETROIT, MICHIGAN, A CORPORATION 0F DELAWARE.

CARBURETOR.

Application filed August 6, 1920. Serial No. 401,576.

T0 all whom it may concern.'

Be it known that I, CHARLES E. WIL- LIAMS, a citizen of the United States, and a resident of Detroit, county of Wayne, and State of Michigan, have invented certain new and useful Improvements in Carburctors, of which the following is a full, clear, concise, and exact description, such as will enable others skilled in the art to which the invention relates to make and use the same, reference being made therein to the accompanying drawings, which form a part of this specification.

It has been customary heretofore to pro vide carburetors wherein an increase of pres-` sure is momentarily applied to the fuel chamber to cause a corresponding discharge of fuel from the nozzle into the mixture passage for starting or for acceleration, one well known form compris ing a piston inter-connected with the throttle in such manner as to be projected into the iioat chamber, either directly into the fuel or into 'a part of the enclosed air space abo-ve the liquid. Heretofore the operation of carburetors of this 'general type, so far as the pressure applying means is concerned, has been the same regardless of temperature, that is, for a. given throw of thc throttle or other operating lever the same fuel displacement has been obtained.

The leading object of the present invention is to secure a richer starting or accelerating mixture in carburetors of this general type when cold than when heated to the usual operating temperature, and to this end I provide heat-responsive means for relieving the pressure so applied to the fuel to a greater extent when heated to normal operating temperature than when'cold; this is accomplished in the preferred embodiment of the invention by the use of a thermally controlled restricted air outlet from the fuel chamber so arranged as to be open to its greatest extent at maximum temperature and to be closed gradually as the temperature falls. It is evident that the invention is not necessarily limited to use in connection with a piston inasmuch as a similar result may be obtained, for example, where the piston is replaced by a diaphragm or other equivalent device; neither is it necessary although it is much to beypreferred that the device operate synchronously with the throttle, since other operating levers or means may be used.

In the preferred construction, the fuel chamber is also provided with the ordinary vent, but it is to be understood that the. vent may be combined with the thermally controlled relief passage in a manner which will be obvious later.

In the drawings:

Fig. 1 is a side elevation of a carburetor showing a preferred embodiment of the invention, parts being broken away.

Fig. 2 is a sectional view looking from the right in Fig. 1, parts being broken away.

Fig. 3 is a fragmentary section on lines 3 3 of Fig. 1.`

1 indicates the carburetor body in the neck of .which is an ordinary throttle valve 2 of any suitable type. The body forms a cover for a float chamber or is normally maintained at a substantially constant level by means of the usual inlet valve (not shown) and float 4. The joint between the upper edge of the bowl and the cover is preferably sealed by packing 5. A suitable nozzle 6, in communication with the float chamber 'at 7 below the level of the fuel passes through the cover and opens into a strangle tube 8, and primary air latter from the vertically extending pas- Sage 8 to mix with the secondary air which enters through a valve controlled passage 9 in the ordinary wa The parts thus far described are mer ly by way of example, and the invention may be applied to carburetors of widely different types.

Formed as a part of or communicating with the float chamber as by means of a passage 12, is a chamber 13 which in the construction shown constitutes a cylinder for a piston 14 the rod 15 of which is threaded for bowl 3 wherein fuel flows upwardly through the adjustment in a split element 16 that is pivotally connected at 17 to an arm 18V fixed to the throttle shaftV 19. Various other functionally equivalentpressure devices and connections may evidently be employed, and it is clear that when the throttle is thrown toward open position the pressure of the air above the fuel is increased, thereby causing an abnormal or `increased discharge-of fuel from the jet or nozzle. l

I am aware that a somewhat similar action of momentarily increasing the discharge from the nozzle may be secured in other ways, in some of which the piston is applied directly to the fuel,r but the construction shown is much to be preferred on account of,

the fact that Vthe increased pressure is applied in what may be termed a more elastic manner, and further because the thermally controlled pressure relief can be much more satisfactorily attained when operating on the air confined above the fuel than would be the case, forexample, were the relief to be by way of a thermally VYcontrolled by-pass for returning more fuelffrom the nozzle passage to the iloat chamber at high temperature than when cold. However, I regard the broader aspects of the invention as applicable wherever a temporary increase of pressure on the liquid is secured and regardless .of the particular manner or means by which it is attained.

In the referred embodiment, a passage 25-262-'-28 is so constructed and leads fro-mthe lower part of the chamber 13 upwardly in such manner as to prevent selfsealing through the splashing of fuel upwardly therein, such as might occur in operation on rough roads, and .has there assoelated with its end portion to open and close the same a thermally controlled element 30 that is preferably in the forln of a blade of ordinary thermostat metal; Other types of thermally controlled devices might be used but that described is preferred because of vits slight cost. It is also evident that the passage 25-26-27-28 may assume'difl'erent shapes but I prefer `to position its upper end, that is, the element 28` in a block 32 that may be either integral with the body or detachably secured thereon as by means ,f of a screw 33. By `locating this block within a housing formed as by means of the walls 34 integral with the body and the detachable cover plate 35proper'protection for the thermal element is secured.

This housing also receives any fuel that may under special circumstances overflow through the passage 25-26-27-28, and a suitable pipe or conduit 384 is preferably provided to return thesame to the main fuel tank or to( some other collecting receptacle (not shown) and "may also supply the air necessary for venting the float chamber maa-16o although the latter may be obtained through a vent or port 36.

The thermostat as intimated above may take various forms, but the U-shaped type,`

attached at one endl to the block 32 by a screw 40 is preferred; and it is also preferred to provide means for varying the initial adjustment of the'blade in respect to the associated outlet port. VAs a cheap and convenient means for this purpose, the thermostat may be slitted to provide an upwardly extendmg tongue 41 arranged to be actedV upon by the adjusting screw 42. The adjusting screw may of course be locked in position Vin various Ways, such, for example, as by splitting the blockV about the threads for the screw and by connecting the divided ends thus formed by a` clamping screw 43. InJ operation, each movement of the throttle towardsV open positionV is accompanied by a corresponding depression of plunger 14 while the air in theffloat chamber attains a slightly superatmospheric pressure (or at least has its pressure increased over that'which would normally exist) and causes an increased discharge of fuel through the nozzle into'the mixture conduit, the precise amount thus discharged for a given throvs7 of the throttle lever at any given degree of rapidity of movement being dependent on the extent of the free opening through the relief passage at the temperature then prevailing, it being understood that the thermo-stat on expansion rises and uncovers the passage 28. The metering or restricting action, being directly effective on the, air, as distinguished from the fuel, permits the use of much larger control passages or restrictions, so that manufacturing is simplified and the control rendered more certain and uniform.

The venting of the ioat chamber, which is necessary to permit the normal supply of fuel therefrom at low temperature to the nozzle, may be effected by an ordinary vent 50, but it is preferred to tap into'the passage 25-26-27-28 preferably` near the upper end thereof, by a passage of less crosssection than the passage 28, as indicatedY atl 51.

I am aware that viarious changes and imodifications, other! thanv those indicated,

may be made withoutl departing from the spirit of the invention," as expressed in the claims.

I claim: A

1. In a carburetor, a fuel mixture conduit, a nozzle opening into said conduit, a fuel chamber leading to said conduit, and pressure creating and controlling means for temporarily variably increasing thepressure on the fuel in said chamber to thereby increase the discharge of fuel to said conduit and to cause a greater discharge under like conditions at low temperatures than at high temperatures.

2. In a carburetor, a fuel mixture conduit having a fuel supplying passage and an air supplying passage opening therein, manually operated means for temporarily creating and applying increased pressure to the fuel in said fuel passage tOLthcreby increase the discharge of fuel to said conduit, andmeans for rendering said manually operated means less operative under like conditionsk at relatively high temperature than at relatively low temperature.

3. Ina carburetor,'a fuel mixture conduit, a fuel nozzle opening into said conduit, a fuel chamber in communication with said nozzle, means for exerting air pressure on said fuel to cause increased discharge from said nozzle at will, and thermally controlled means for rendering said first named means more effective under conditions of relatively low temperature than under conditions of relatively high temperature.

4. In a carburetor, a fuel chamber wherein liquid fuel is normally maintained at a substantially constant level, a fuel mixture conduit, a nozzle communicating with the fuel chamber and opening into said conduit, and thermally controlled means for momentarily displacing fuel from said chamber to discharge the same through said nozzle in less quantities when warmed up to the usual operating temperature than when cold.

5. In a carburetor, a covered fuel chamber wherein liquid fuel is normally maintained at a substantially constant level, a mixture conduit in communication with said chamber, an air passage leading upwardly to a point considerably above the cover of the fuel chamber, an overflow conduit in which overflow of fuel from said air passage is received, and a heat controlled ele- `ment restricting said air passage.

6. In a carburetor, a fuel chamber, a mixture conduit communicating therewith, heat responsive means associated with the fuel chamber to relieve air pressure therein to a greater degree under relatively high temperature than under relatively low tempelature, and manually controlled means through which air confined in said chamber is temporarily placed under superatmospheric pressure to cause increased discharge of fuel to said conduit.

7. In a carburetor, a fuel mixture conduit, a fuel chamberin communication with said conduit and having a vent, and airV pressure relief passage for said chamber separate from the vent, means for subjecting the air confined in said chamber to super-atmospheric pressure, and means associated therewith forl restricting relief o-f said pressure throughjsaid relief passage to a greater extent when cold than when warm.

` 8. In a carburetor, a body forming a. fuel mixture conduit, a fuel chamber iu communication with said conduit, a detachable block mounted on said body, there beingan air passage leading from said chamber and through said block, and heat controlled means carried by the block andlending to variably restrict the passage through said block.

9. In a carburetor, a fuel mixture conduit, a fuel chamber in communication therewith, a passage leading from the upper part of the fuel chamber to the atmosphere,

a heat responsive device tending to variably restrict said passage, means for housing and protecting said device, and manually controlled means for temporarily increasing the air pressure in said fuel chamber to cause increased discharge of fuel into said conuit.

10. In a carburetor, a fuel mixture conduit, a fuel chamber in communication therewith, a passage leading from the upper part of the fuel chamber to the atmosphere, a heat responsive device tending to variably restrict said passage, a housing for said device, and means for conducting liquid that may pass through said passage into the housing away from said housing.

11. In a carburetor, a fuel mixture conduit, a fuel chamber in communication therewith, a passage leading from said chamber to the atmosphere, la housed block into which said passage extends, said block being detachable from the carburetor, a thermostat carried by the block and detachable therewith from the carburetor for variably restricting said passage.

12. In a carburetor, a fuel mixture conduit, a fuel chamber communicating'therewith, a passage leading from said chamber to the atmosphere, means for creating super-atmospheric pressure in said chamber and a thermostat for restricting said passage to a greater degree when cold than when warm.

13. In a carburetor, a fuel mixture conduit, a fuel chamber communicating therewith, a passage leading from said chamber to the atmosphere, means for .creating super-atmospheric ressure` in said chamber, a thermostat or restricting said passage, and means for manually adjusting said thermostat to vary its restricting action.

14. In a carburetor, a fuel mixture conduit, a fuel chamber in communication therewith to'supply fuel thereto when suction from the engine is applied to said conduit, means for restricting the supply of fuel to said conduit when warmed up by the operation of the englne as compared to that supplied when the engine is cold, said means including an air passage leading to said' chamber above the level of the fuel therein, a throttle for said conduit, and means inter-connected with said throttle for teinporaril increasing the air pressure in said cham er.

15. In a carburetor of the class described, a fue] chamber having a passage for relieving air pressure therein, a thermostat operative to increasingly restrict said passage in fall of mperature, and means 0p erative on the mid-portion of said thermostat for adjusting it in respect t0 said passage.

In testimony whereof I aix my signature. D

CHARLES E. WILLIAMS. 

